08-11-2016, 02:39 AM (This post was last modified: 08-11-2016, 02:41 AM by Arne.)
Hi,
I'm building a DIY led light and for me it would be great to have the possibility to control my light fan (pwm) based on temperature.
With a sensor build in the led lights, when the lights are cold no fan is running.
When it's hotter or the lights get warmer the fan starts running a little faster.
Hi Arne, I'm not sure if I will add that, right now you can use 1 of the 16 LED channels to control the speed of fans. You can have the fan speed up as the lights get brighter and slow down as the lights dim. When the lights dim to off, using the expansion hub, you can keep the fan running until it hits a temperature which then turns off the fan completely. Using the different settings you can keep the lights at a certain temperature but it wouldn't be using temperature. With the expansion hub you can also create a rule so the power to the light goes off if the temperature goes over a set value, this is good if the cooling fans quit working.
(08-11-2016, 02:16 PM)Rob F Wrote: Hi Arne, I'm not sure if I will add that, right now you can use 1 of the 16 LED channels to control the speed of fans. You can have the fan speed up as the lights get brighter and slow down as the lights dim. When the lights dim to off, using the expansion hub, you can keep the fan running until it hits a temperature which then turns off the fan completely. Using the different settings you can keep the lights at a certain temperature but it wouldn't be using temperature. With the expansion hub you can also create a rule so the power to the light goes off if the temperature goes over a set value, this is good if the cooling fans quit working.
Great idea Rob. I wanted to place a DS18B20 in each heat sink, but could only accommodate one as I ran out of pairs on my DB-25 connector and feed cables. You could "pair" the fan to the same schedule of say your blue/white light leds lighting schedule to shadow the approximate peak temp times. I have been using your graphs to monitor my light temps for weeks now. They consistently peak between 12:30 pm and 5:30 pm. I am currently using a 12v DC fan. There are hacks on the web that show how to turn a 3 pin 12V fan into a 4 pin pwm controlled fan.
The attached conversion is from an article I saved from TechPowerUp.
It was titled
"So you want PWM control of your new CPU fan?
Discussion in 'Cases, Modding & Electronics' started by Lazzer408, Oct 29, 2009." in case you want to look for the complete article.
Rob, I was a little more ambitious on your behalf, in what you might be able to do down the road for the DIY led light builders out there. I would love to see some AI in the code that can monitor the heatsink temps, not just ramp up a fan, but rather if they reach a critical mass point, drop all intensities by a preset or adjustable point (say 20-30%) to allow a cool down without too much dimming to really affecting the daily cycle for the corals (plants for you F/W guys ;-) ). Lights can return to full when the temp drops. Also tie a notification in with alarms. If if happens repeatedly, like when you're away, you know to start trouble shooting!
Still a great workaround Rob... Lucy, you have some rewiring to do!
Hi Steve, yeah its a good workaround, with the graphs its easier to setup. I like your idea with the lights dimming if temp goes to high, it would be good for corals. For now you can set a web alert to monitor the temp of the light so you get a notification if it goes to high so you know to look into it. You can also set a rule to turn the light off when this happens and back on when its cooled down but yeah that might not be so good for the corals. Soon I will be adding optional alerts to the rules so you know when they go off.
Using that TIP120 transistor you can do a lot of things. Technically you can use any of the 16 LED channels for anything if you're happy with using it in the schedules of the lights. With the converter I sell you can also connect digital power heads and have them ramp up or down during the 4 different light schedules.
Here's a page showing some basic examples that are easy to setup.
Well, this is an interesting subject... ;-)
I see it a bit different, I think when you have to dim the lights, there's something wrong with the design of your lamps...
I want to reduce fan noise as much as possible.
if you want to silence them you could also build a ventury style duct lined with acoustic dampening material.
you would be able to get a 50-80% reduction in noise if build properly
but you can also use the PWM to run 2 pin DC fans with a transistor, it just depends on what your goal is..
08-12-2016, 03:18 AM (This post was last modified: 08-12-2016, 04:45 AM by Arne.)
I don't have enough room for a "ventury style duct line" and that's not the approach I was looking for.
The picture Steve posted shows is not what I'm looking for either, this also relies on a PWM output pin.
I don't want to be over exaggerating, all I was hoping for was a PWM output pin based on temperature, that's all... ;-)
I can build myself a PWM temp controller with just a few parts, no problem.
I just thought it might fit well into the philosophy of Robo-Tank as a controller...
Your right Arne, its not normal to hit a high temp with the lights running, I think Steve is just concerned if it happened his corals would feel it. At some point I will probably add something like that, I just don't want to promise anything. You will be able to slow down the speed of the fans to match the amount of cooling you need 4 times a day, once its setup it will be the same. The temperatures for the light are typically identical everyday. When I go through my graph for the light it almost looks the same for every day. You can see when it peaks and speed up the fan, then verify with the graph you got the temp down where you want it. If you see periods where temps are low you can slow down or turn off the fan during that period.
(08-11-2016, 11:36 PM)Arne Wrote: Well, this is an interesting subject... ;-)
I see it a bit different, I think when you have to dim the lights, there's something wrong with the design of your lamps...
I want to reduce fan noise as much as possible.
Hello Arne and welcome to the forums,
Yes, proper led choice, placement, heat sink size, spacing and hood ventilation SHOULD make for normal temperature operations. I have that. I also had a fan FAILURE. That will cause a temp rise in the best of designs. Noise is not my primary concern as my preference is for hooded aquariums and I only have one that is rimless / hoodless with a free hanging light above.
I would rather take advantage of the alarm and control capabilities that Robo-Tank has than coming home to a fish fry. Been there, done that (bad heater, bad BAD heater!)
Going forward, I look for quieter fans that incorporate Teflon nano bearings and noise cancelling adapters and that are even IP56 splash resistant. An 11 blade design can help with a higher air flow. No more cannibalizing an old computer for me!
08-13-2016, 01:42 AM (This post was last modified: 08-13-2016, 01:43 AM by Arne.)
Thanks Steve, thanks Rott... ;-)
Yes Steve, I will sure make use of the Robo-Tank alarms.
I have to see what room I have left to optimize the fans.
Hopefully no fried fish for me but it's still $&%# when you come home and see this...
Sorry it happened !
